Siberians are said to be the direct ancestors of Native Americans. These Siberians moved into the Beringian land bridge and from there crossed into North America and spread across the whole continent, peopling the Americas, or at least that is what the story says. But what are the facts?
A recent paper: The population history of northeastern Siberia since the Pleistocene, by Martin Sikora et al., Nature vol 570, pp. 182 June 13, 2019, https://doi.org/10.1038/s41586-019-1279-z, describes their findings after sequencing the genomes obtained from 34 ancient remains across Siberia. These genomes span ages ranging from 600 to 31,600 years ago.
These genomes also include the northernmost pleistocene remains found in Siberia, at Yana RHS: they are the earliest direct evidence of human presence in northeastern Siberia, a population that they refer to as Ancient North Siberians (ANS).
Their conclusions are interesting: (bold is mine)
"We find that—despite the complex pattern of population admixture throughout the past 40,000 years the first inhabitants of northeastern Siberia (represented by the Yana RHS individuals) were not the direct ancestors of either Native Americans or present-day Siberians, although traces of their genetic legacy can be observed in ancient and modern genomes across America and northern Eurasia.
These earliest ancient Siberians (the ANS) are known from a handful of other ancient genomes (those of the Mal’ta and Afontova Gora individuals); they are the descendants of one of the early modern human populations that diversified as Eurasia was first settled by our species, and are thus highly distinct.
The ANS were later partially assimilated with a group with East Asian affinity who formed the Ancient Palaeo-Siberians (represented by Kolyma1); this group also probably once had a wide geographical distribution across northern Eurasia. The genetic legacy of Ancient Palaeo-Siberians among present-day Siberians is more limited, being restricted to groups in northeastern Siberia."
They found that "Despite their extreme northeastern Siberian geographical location, the Yana RHS individuals are genetically closer to West Eurasians".
They have to look to a later date to find a Siberian that is closer to Native Americans: "We find that the Kolyma1 individual (dated to 9.8 ka) who represents a lineage that formed after about 30 ka, which we name ‘Ancient Palaeo-Siberian’ documents the first major genetic shift that we observe in the region ... Principal component analysis, outgroup-f3 statistics and mitochondrial DNA and Y chromosome haplogroups (G1b and Q1a1b, respectively) demonstrate a close affinity between Ancient Palaeo-Siberians and present-day Koryaks, Itelmen and Chukchis, as well as with Native Americans."
But Kolyma1 remains, found in northeastern Siberia, close to Beringia, are less than 10 ky old! So she cannot be an ancestor of the older American population which is now believed to have reached America at least 16 kya. Could Kolyma1 be the outcome of a backflow into Siberia, from America? Only about 66% of her genes is similar to that of Native Americans.
So Kolyma1 is the closest they could find to American Natives, however she isn’t an ancestor. Most of her genome belongs to the "Ancient Paleo-Siberian" lineage which split from that of the Native Americans some 24,000 years ago.
Interestingly, they report that "A signal of Australasian ancestry that has been observed at a very low frequency in some modern and ancient South American populations is not evident in any of the ancient Siberian or Beringian samples sequenced here, or in previous studies".
The study concludes that "the majority of Native American genetic ancestry is likely to have originated in northeastern Siberia rather than south-central Siberia, as has been inferred from modern mitochondrial and Y chromosome DNA."
To sum it up, the northernmost of the early Siberians (Yana) are not related to the people who supposedly peopled America. The later Kolyma woman is similar to but not an ancestor either, she is actually a later arrival in the area, when she died, America was already inhabited!
There is a paucity of remains between Yana and Kolyma1 which means that we have to wait for more remains to be discovered and studied before this issue is settled for good.
Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2019 by Austin Whittall ©
A good summary of current knowledge, but where is this all leading Austin? To me it seems that you're trying to imply that the Americas, were one of the sources of human evolution. In other words the 'Out of America' idea. Whilst I agree that hominins were in America much earlier than currently accepted, there is very little evidence of it compared to the 'Out of Africa' model, which has mountains! Come on Austin get real. NeilB
ReplyDeleteThanks for your coment Neil. What is interesting is the gap between both Siberian specimens, from Yana and Kolyma1, and the changes in the genetics of both individuals. Clearly a lot was going on over there at the time when H. sapiens entered America.
ReplyDeleteAlso the "Australasian" ancestry did not seem to come via Beringia so it probably crossed the Pacific Ocean to reach America.
Dear Austin, thanks for your calm reply. I got a bit hot headed there!
ReplyDeleteYou are right, it does seem the Yana people contributed negligibly to the native American gene pool. Also Kolyma1 could be evidence for (back?) migration from the Americas to east Asia. As to when the Austronesian signal found in some S. American groups got there or by what route, I think the jury is still out.
I have admired some of the pieces of evidence you have assembled over the years that question the orthodox theories about the peopling of the Americas.
In particular, the diversity of languages and the basal variety of some human pathogens in the Americas have yet to be explained satisfactorily by mainstream scientists. Therefore you have brought forward evidence that the migration of humanity to and from the continent is not as simple as we currently believe. NeilB
You didn't include the last paragraph of their conclusions.
ReplyDelete"which implies that the majority of Native American genetic ancestry is likely to have originated in northeastern Siberia rather than south-central Siberia"